We sequenced the complete mitochondrial genome of a widely distributed Palearctic bat restricted to mountain ranges, the alpine long-eared bat, Plecotus macrobullaris. We integrated ecological niche modelling, approximate Bayesian computation (ABC), measures of genetic diversity and Bayesian phylogenetic methods to study the effect of differences in the extent of glaciation events on the evolutionary history of separate lineages.

Based on the complete mitochondrial genome and inference of evolutionary history we found contrasting population-level responses to Pleistocene climatic oscillations.

We show that geographical variation in the extent of glaciation events across mountain systems in the Palearctic yielded complex population dynamics with contrasting patterns of expansion and retreat between western and eastern lineages.

This study offers an example of population-level variations in the effects and long term consequences of climate change.